Deep well motor drill



INVENTOR. MAR/0N A. GARE/SON BY 2 Sheets-Sheet l Arm/v L STEELE M. A. GARRISQN DEEP WELL MOTOR DRILL Feb. 5, 1963 Filed Dec. 1. 1958 ATTORNEY Feb. 5, 1963 E 3,076,514

M. A. GARRISON DEEP WELL MOTOR DRILL Filed Dec. 1, 195a 2 Sheets-Sheet 2 INVENTOR. BY MA R/OA/ A. GAR/P/s /v A y/v/v A. STEELE ATTORNEY United States Patent 3,076,514 DEEP WELL MOTUR DRILL Marion A. Garrison, Denver, Colo, assignor to Empire Oil Tool (30., a corporation of Colorado Filed Dec. 1, 1958, Ser. No. 777,454 6 Claims. (Cl. 175-107) This invention relates to deep well drilling equipment and more especially to drill bit apparatus employed at the bottom of drill pipe strings used in the rotary drilling of oil wells.

An object of the invention is to provide drill bit apparatus which may be positioned in the lower end of a drill pipe string and in turn be presented in proper drilling position by such string and contain within itself a rotary motor actuated by the pressure of the usual drilling mud which is pumped down the string to the bit and up the well hole outside the drill string to the surface for separation of the entrained cuttings formed by the rotating bit.

A further object of the invention is to provide an effective and practical drill bit arrangement and driving means therefor to be used at the bottom of a deep well drill string whereby the drill bit may be rotated without the usual rotation of the drill string from the surface of the well as required in conventional rotary drilling.

Another object is to provide a relatively inexpensive rotary drill operating system that can be effectively used at the lower end of the deep well drill string whereby to dispense with the usual costly rotary table and drive mechanism therefor heretofore required in rotary drilling of deep wells.

A still further object of the invention is a novel drilling combination of the indicated character, a novel posit-ive displacement fluid motor actuable by conventionally pressurized drilling mud, and a novel thrust bearing and bearing assembly for disposing drill bit driving means hereof in a bottom section of drill pipe by which the drill bit is presented to the bottom of the hole being drilled.

Other objects of the invention and the various features of construction thereof will become apparent to those skilled in this art upon reference to the following specification and the accompanying drawings wherein:

FIG. 1 is principally a vertical elevation of a lower section of drill pipe from whose bottom end projects a conventional bottom hole drill bit carried upon a projecting portion of a typical threaded box element rigidly mounted on the lower end of a drill shaft which extends through a thrust bearing assembly (seen in broken lines) and which is driven from a rotor shaft of a positive displacement fluid motor thereabove (which also is shown in broken lines);

FIG. 2 is a vertical sectional view on an enlarged scale of the upper portion of the fluid motor of PEG. 1;

FIG. 3 is a similar vertical section showing the lower portion of the fluid motor and the upper portion of a coupling joining the driven rotor shaft of the motor to the upper end of the drill shaft;

FIG. 4 is a similar vertical section showing the rest of the connection to the drill shaft and the thrust hearing assembly positioning the drill shaft and its box element in the lower portion of the pipe section carrying the apparatus;

FIGS. 5, 6 and 7 are cross sections taken on the lines 5--5, 6-6 and 7-7 of FIGS. 1, 2 and 3, and on the scale of FIGS. 2 and 3 as to FIG. 5 and slightly larger as to FIGS. 6 and 7;

FIG. 8 is a cross sectional composite of FIGS. 6 and 7 to show port relationships, and may also be considered as taken on the line 6-6 of FIG. 2;

FIGS. 9, and 11 are cross sections taken on the lines 9-9, Ill-10 and 11-41 of FIGS. 1, 3 and 4, and on the scale of FIGS. 3 and 4; and

FIG. 12 is a large scale vertical sectional fragment showing one of the thrust bearings seen in FIG. 4.

Having reference to the drawings, the motor and drill structure of this invention is carried within a section or length of non-rotating metallic pipe 10 which is a section of pipe known in the oil fields as drill pipe, being, in ordinary rotary drilling procedure, a length of the so called drill string which is made up from sections of the same drill pipe and extends from the earths surface at the top of the well, where it is rotated, down to the bottom of the well to rotate the usual drill bit. In practice with the present improvement, the pipe section 10 is carried also at the lower end of a pipe string, which string, however, does not require rotation but nevertheless serves the functions of supporting the motor drill hereof and of conducting the pressurized drill mud down to the drill bit and returning such mud up through the well hole outside the pipe string with the cuttings formed by the drill bit to convey the cuttings to a settling basin at the surface, as usual.

The pipe section 1% is attached to the lower end of the main pipe string by a suitable joint which may be a direct box-and-pin threaded connection or a short conventional sub 11 usually of smaller internal diameter than that of the pipe, as in FIG. 1. The lower end of this motor drill combination employs any standard or preferred bottom-hole drill bit 12 which drills at the bottom of the well hole below the lower extremity of the pipe section 10. However, the bit 12 is not directly attached to the lower end of pipe section It) nor rotated thereby, but is instead directly attached to the bottom of a bit-mounting in the form of lower box element 14 rigidly connected (preferably integrally) to the lower end of a rotary drill shaft 15, such shaft element 15 rotating in a bearing 16 in the lower end of the pipe section lit, as best seen in FIG. 4.

Rotation of the drill shaft 15 in the pipe section 10 is effected through a splined coupling 18 which connects the upper end of the drill shaft 15 with the reduced lower end of an elongated driven rotor shaft 29 of a positive displacement fluid motor, which is generally indicated at 22, and has an elongated outer motor housing 24 fixed within the pipe sectionltl through an intervening spacing means and partition sleeve 25 which acts as a dam and diverter between the upper and lower annular drilling mud passages or spaces 26 and 27 (FIG. 2) between the housing 24 and the pipe section It). The sleeve 25 is welded at 25a to the housing 2.4- and supports the housing 24 inthe pipe section 10 through the. agency of an annular series of short countersunk screws 28 passing through both the pipe it) and the sleeve 25 and also part way into the housing 24.

The upper end also of the driven rotor shaft 20 is reduced, thereby providing between the rotor shaft ends an intermediate enlarged rotor body seen in FIGS. 6, 7 and 8. Such upper end is mounted at the top of the motor housing 24 by a bearing unit 30, and the lower reduced end of the rotor shaft 20 is positioned in the bottom of the housing 24 by a similar bearing unit 32.. Rotation is imparted to the rotor shaft 20 by the action of the conventional pressurized drilling mud which is pumped into the drill string at the earths surface to supply the drill bit 12. Such mud enters the motor housing 24 from the upper annular space 26 above the dam or partition sleeve 25 through inlet ports 34 in the two indicated sections of the motor housing above the sleeve 25, and the mud leaves the motor housing through the several indicated outlet ports 35 in the several indicated sections of the motor housing 24 below the partition sleeve 25 to return to the lower annular mud space 27, whence it con- 3 tinues downward toward the drill bit 12. The greater number of outlet ports 35 over inlet ports 34 provides for quick pressure drop and maximum motor efi'iciency. Mud travelling through the lower annular space 27 passes through a series of ports 33 (FIGS. 4, l and 11) annularly arranged in each of a vertical series of thrust bearing units 4% of a thrust bearing asesmbly 42 which serves to transfer the load of the drill string to the drill bit 12, and also to support the drill shaft 15 in the pipe section 1 as later to be described. Drilling mud is also passed from the drill string into the top of an axial bore 44 in the rotor shaft through a flow bean 44a disposed in the top thereof, and from the bore 44 through an aligned axial bore 45 in the drill shaft 15 to a chamber in the interior of the box element 14 of the drill shaft where this mud stream (FIG. 4) commingles with mud from the ports 38 of the thrust bearing assembly 42, entering the box element 1 through an annular series of approximately radial ports 46. This combined mud flow then passes a check valve 48 in the chamber of the box element 14 and pass-es thence through the usual bore in the drill bit 12 to lubricate the cutting elements thereof and pick up cuttings pro duced thereby which are circulated up through the well hole outside the drill string. The Well hole is typically of greater diameter than that of the pipe section It) and the drill string because the typical bit 12 has an effective overall diameter greater than the drill string diameter, as indicated in PEG. 1.

The Fluid Motor Considering the elongated fluid motor 22 in detail, the outer motor housing or shell 24, containing the rotor 2%, is suspended in the pipe section 10, as previously stated, by the welded spacer and partition sleeve and the short screws 28. The housing 24 provides a plurality of motor sections, which in the form illustrated are eight sections, these being the two inlet sections above the sleeve 25 containing the inlet ports 34, a third section coextensive with the sleeve 25 and having no ports, and five lower sections having the outlet ports 35. These motor sections are conveniently of equal length, although the top port 34 and the bottom port 35 may be slightly shorter than the other ports for proper control of mud flow, as seen in FIGS. 1, 2 and 3. Each of these motor sections is provided with a renewable wear liner 5t} fitted into the inner wall of the housing 24, all of the liners being of the same length and abutting one another end-to-end between the bearings 30 and 32. The liners of course contain ports corresponding and registering with the ports 34 and 35.

The driven rotor shaft 20 is reduced to the relative size and diameter at both ends as seen in FIGS. 2, 3 and 5 to enter the upper and lower bearings 30 and 32. The upper bearing 30 includes a headed bushing or flanged sleeve bearing 52 which is threaded into the top of the motor housing 24 and down into contact with a washer or bear ing plate 54 disposed on top of the upper liner 5t! and just above the enlarged body portion of the rotor 29 as presently to be explained. The sleeve bearing 52 is provided with a bonded rubber bearing liner 55 in which the respective reduced end of the rotor 20 is received and in which it rotates. The liner 55 is flanged at 55a to overlie the top surface of the sleeve bearing 52 and is bonded thereto to provide a bearing surface upon which rotates a bearing nut 56. The nut 56 is secured to the projecting upper end of the rotor shaft Zil by being threaded thereon as shown in FIG. 2 and by being anchored on the shaft end by a cup-like lock nut 57 which is tapped to receive the threaded flow bean 44a passing drilling mud to the bore 44 of the shaft 20 as previously described. The bonded rub-her flange 55a thus in itself provides a relatively thin rubber bearing for the under side of the hearing nut 56 to work upon. Such a rubber is desirably a synthetic oil-resistant rubber typified by a buna-N rubber or neoprene, and is of a grade to meet the requirements of a good bearing rubber such as a Shore hardness of 70 or as Well understood in the rubber trade. To provide for good lubrication by the drilling mud itself, the inner wall of the rubber liner 55 and the top surface of its flange 55a are provided with shallow grooves 58 which receive and pass a lubricating amount of the mud. Thus, the rotor shaft 29 freely rotates in the rubber liner 55 of the bearing sleeve 52 while its bearing nut 56 rotates on the rubber flange 55a.

At the lower end of the motor housing 2-4, the lower reduced end of the rotor shaft 20 rotates in a similar sleeve bearing 62 threaded at 66 into the lower end of the motor housing 24 and supporting a washer or bearing plate 64 under the bottom housing liner 5t] and slightly below the enlarged body portion of the rotor 2 Here again the sleeve bearing 62 is provided with a rubber liner 65 and a flange 65a thereof which are bonded to the sleeve bearing 62 and its under face. A bearing nut 66 is threaded on the lower end of the shaft 29 as seen in FIG. 3 and is secured in place by a lock nut 67. The rubber liner 65 and its flange also are grooved to receive lubricating mud as indicated at 68. Thus, the opposite ends of the rotor shaft 20 are rotatably mounted in the bearings 36 and 32, which by reason of their rubber liners 55 and 65 provide a limited amount of yieldability insuring proper functioning of the rotor 20 in the motor housing 24.

Fluid Motor Construction Efficient operation of the drill shaft 15 by the rotor 20, which is rotated by the pressurized drilling mud, is at-' tained by reason of the construction of the motor housing 2 and the enlarged rotor body of the rotor shaft 20 between its reduced ends. This includes two elongated drive mud chambers 79 between the motor housing 24 and the rotor shaft 2% and extending the full length of the transversely enlarged rotor body of the rotor shaft 2%, as indicated for example in FIG. 6. Each chamber 70 receives drilling mud through its inlet ports 34 and discharges such mud from its outlet ports 35 which collectively may provide two to three times as much area as the inlet ports 34-, whereby to effect quick pressure drop and maximum driving efficiency.

The pressurized mud entering through the ports 34 works against a plurality of vertical folding rubber vanes or blades 72 which extend substantially the full length of the enlarged rotor body of the rotor shaft Zil and are disposed in corresponding vertical channels 73 in the rotor surface, so that their outer or flap halves flex between extended driving positions and fully collapsed positions within the channels 73. The collapsed positions are caused by engagement of the vanes 72 with a pair of diametrically opposed elongated arcuate vertical separator strips 74 which also extend the length of the enlarged rotor body to fill the annular space between the motor housing liners 5t and the outer wall of the rotor body and divide such annular space into the two equal vertical mud chambers 70 mentioned. The separator strips 74 are secured to the motor housing 24 by screws 75 countersunk in the outer wall of the housing and threaded into the strips 74 as shown, the liners 55, being also retained by such screws 75. The inner halves of the vertical vanes 72 are secured in the bottoms of the channels 73 by elongated thin flat retainer strips 76 on the outer faces thereof and screws 77 countersunk in the vane flaps and strips 76 and threaded into the rotor shaft 29. Thin metal reinforcement strips 7% are embedded in and bonded to the working face of each swinging vane flap.

The number of vanes 72 desirably is an even number and is shown as being a preferred four for the plurality of mud chambers 79 shown as being two. These vanes are equidistantly spaced around the rotor 29, and the channels or pockets 73 therefor are slightly less in width than the width of the separator strips '74, the spacing between the channels 73 approximating or being slightly greater than the width of the separator strips 74. The inlet ports 34 are diametrically opposed for the respect tive chambers 70, and each such port 34 is disposed immediately at that edge of the near separator strip 74 which faces in the direction of travel of the rotor shaft 29 which is a clockwise direction in FIGS. 6 and 7, and such edge of the respective strip 74 may be termed the near edge of the strip and considered to be located at the near side of the respective chamber '70, as related to the remote strip 74 at the far side of the chamber.

Pressurized mud entering the inlet ports 34- in the upper sections of the motor from the annular space 26, outside the motor housing 24 above the diverter partition 25, now impinges upon the extended flaps of the vanes 72 and imparts the required rotation. These vanes will normally assume the indicated extended positions because of the rubber used in their construction, which preferably is an oil-proof synthetic rubber such as neoprene or the buna-N type familiar to the industries and preferably used for all other rubber parts called for herein. It may have a Shore hardness of around 60 or 70. Under the mud pressure, which acts to force the vanes to their extended positions, they are checked in such positions because of the presence of the insert and reinforcement strips 78 and the presence of stop walls 79 at the far edges of the channels '73 which are directed rearward at a small angle or away from the direction of travel so that the outer edges of the vanes 72 frictionally engage with the inner walls of the wear rings 5G and prevent pressurized mud from being forced past the vane edges.

The pressure mud entering the inlet ports 34 into the vertical chambers 70 against the extended vanes 72 then passes downward in such chambers from the upper sections of the motor through the section within the partitions 25 (where there are no ports) and passes thence downward into the lower motor sections having the outlet ports 35. These outlet or discharge ports 35, as indicated in FIGS. 7 and 8, are disposed alongside the near edge of the remote separator strip 74 for the respective mud chamber 7ft, that is, adjacent the near edge of the strip at the far side of such chamber. When the descending mud columns in the chambers 7t} reach the various discharge ports 35, the rotor shaft having been correspondingly rotated, the mud returns to the annular space between the pipe section it} and the motor housing 24 below the diverter partition 25 as indicated at 27.

By employing more propeller vanes 72 than vertical chambers 'i'tl, such as the four vanes 72 for the two chamhere 70 illustrated, vane surfaces are alwayspresented to the incoming pressurized mud when other vanes are collapsing and passing the separator strips 74-. In effect, with the four vanes 72-, two mud columns are formed in each chamber 7% by the intervening vane 72, so that, when the lower portion of an advancing vane 72 is reaching the discharge ports of the respective mud chamber 70, a trailing vane has reached the respective inlet ports 34 and bypassing of pressure mud from inlet ports 34 directly to outlet ports 35 is prevented.

By these means, with the normal high mud pressure used in drilling oil wells and the like, high speed and high power rotation are easily imparted to the rotor shaft 20, the drill shaft 15 and the drill bit 12. It is noted that the rear edges of the separator strips 74 toward which the vanes 7'2 travel are beveled to eifect ready collapse of the vanes into their vertical channels or pockets 73.

The Thrust Bearing Assembly The previously mentioned thrust bearing assembly 47. (FIGS. 1 and 4) performs multiple functions, a principal one of which is to transfer the load of the drill string to the drill bit 12 by way of the drill shaft 15 for proper imposition of weight upon the cutting elements of the bit during drilling. The bearing assembly 42 also serves for suitably supporting the drill bit 12 and the drill shaft 15 in the pipe section it? on the lower end of the drill string when running the outfit into the well hole or pulling it out. Additio'nmly this assembly 42 provides an 6 elongated bearing structure for properly aligning and positioning the drill shaft 15 and the drill bit T2 in the lower portion of the pipe section 10 along with the bottom centering bearing 16 disposed about the upper portion of the bit-carrying box element 14 0f the drill shaft 15.

The bearing assembly 42 is made up of a plurality of vertically aligned thrust bearing units 40 of sufficient number to perform the required function with complete success. For example, 15 to 18 or 20 of these units may be disposed about the drill shaft 15 and within the lower portion of the pipe section lit Each unit so includes a stator element tit) positioned in the drill pipe section it) and a rotor portion keyed to the drill shaft 15, there being disposed between the stator and rotor portions an annular rubber contact ring 82 of channeled or C-Shaped cross section and preferably bonded to the stator element as within the locus of the annular series of slots or mud ports 38 previously described. Each rotor portion comprises a spacer ring 83 keyed to the drill shaft 15 and against which the rubber contact ring 82 bears, and also includes an annular thrust plate 84 between adjacent spacer rings 82; and also between the sides of adjacent rubber contact rings 32, as seen in FIGS. 4 and 12. Thus, the rubber contact rings 82. bear against adjacent annular thrust plates 34 at their upper and lower sides, and also against the upright spacer rings 83 at their bottom portions. The rubber contact rings 82 thereby constitute the principal contact or bearing surface elements of the thrust bearing assembly.

As also seen in FlGS. 4 and 12, each stator element 8% is T-shaped in cross section and its channeled rubber ring 322 is fitted over and bonded to the annular stem of the T-shape. Each spacer ring 83, which is positioned between the thrust plates 84 of adjacent thrust bearing units 4t prevents or limits compression of the respective channeled rubber ring 32 between the thrust plates 84. The proportional part of the drill string load is thus transmitted to the respective thrust plate 84 from the stem of the stator through the lower side of the channeled ring 82, the outside wall of the bottom of the channel working against the adjacent wall of the respective spacer ring 83. Adequate lubrication of these parts is furnished by the passing mud through the medium of small grooves 85 in the outer wall or" the various portions of the rubber rings 82, as indicated in both H68. 4 and 12. Both the spacer rings 83 and the annular thrust plates 84 are held against rotation on the drill shaft 15 by keys S6.

The proportional parts of the load of the drill string are thus collectively transferred to the spacer rings 83 and the thrust plates 84, and finally by the lowest thrust plate 84 to a load or pressure transferring washer or collar 87 bearing upon a shoulder 83 at the bottom of the drill shaft 15 just above the box element 14 and the mud ports as feeding thereto.

The uppermost spacer ring 83 is retained on the drill shaft l5 by a nut 96 threaded on the adjacent upper portron of the drill shaft 15, the lower end of the nut 90 bearing upon the top of such upper ring 83. Such position of the nut 99 is assured by a lock nut 91 thereabove located below splines 92 on the top portion of the shaft 15 which splines are received in a lower sleeve 94 of the coupling 18, as later to be described. The series of stator elements 89 of the thrust bearing units 4% is bound in aligned position in the pipe section it) between an upper anchored load transfer sleeve or thrust ring 95 secured to the inner wall of the pipe section 10 by plug welds 96, and a lower or bottom spacer ring or sleeve 98 fitted within the pipe section Til under and in contact at its top with the lowest stator element 80 and hearing at its bottom upon the upper edge of a somewhat elongated bearing sleeve 99 threaded into the lower end of the pipe section it). This sleeve 9? contains and carries the rubber sleeve bearing 16 which 'is bonded thereto'and in which l a corresponding upper portion of the box element '14 of the drill shaft 15 containing the check valve 48 is received and in which it rotates. The lower end of the sleeve 3'? projects from the pipe section it? and is there provided with wrench holes 9% for turning the sleeve up into tight position against the spacer 93 to force the stator elements together and up against the anchored transfer sleeve 95.

The Coupling The drill shaft 15, which is mounted in the lower end of the pipe section by the thrust bearings 4% as above described, is rotatingly driven by the rotor shaft of the fluid motor 22 through the previously mentioned coupling l8 which is spring loaded to provide an upthrust feature and is best shown in FIGS. 1, 3 and 4. This coupling includes the mentioned male lower sleeve 94 receiving the splines 92 on the upper end of the drill shaft 15, and a female upper sleeve 16:? having an internally splined lower box 1G2 receiving external 163 on the top of the lower coupling sleeve 94 (FiGS. 3 and 9). The female coupling sleeve ltlh also has an upper box 104 which is internally splined to receive splines m on the lower end of the rotor shaft 49.

Since it is important, for reasons presently to be explained, to apply an up-thrust to the lower end of the rotor shaft 26, a short length of heavy compression spring 110 is used around the lower end of the rotor shaft 26 above the female upper sleeve ftllil. For this purpose, an annular flanged nut-like spring seat 112 is adjustably threaded down over the box 184 of the coupling sleeve 1% with its flange surrounding the reduced lower end of the rotor shaft 2 9 to provide a seat for the lower end of the spring 11%, and adjustment is maintained by a locknut 114 also threaded onto the box 164. The upper end of the spring 115) bears against the under side of the previously described locknut 67 for the hearlug nut 66 thereabove.

From the foregoing it is apparent that a splined driving connection between the rotor shaft 2% of the fluid motor and the drill shaft is within the thrust bearings 49 is provided through the indicated splines 92, 163 and 1'35, and that the spring Ht) acts to stabilize the resultant joints and to provide relative up-thrust on the lower end of the rotor shaft 2t! through the nuts 66 and 57 and down-thrust on the upper end of the drill shaft 15 by way of the lower coupling sleeve 94 and the locknut 91 on which it bears.

It is to be noted that the spring 110 acts to hold the splined lower end of the rotor shaft 2% high enough to clear an annular series of radial mud ports 115 which are disposed in the lower larger portion of the upper coupling sleeve lttl at a position which also is above the upper end of the lower coupling sleeve 94. Also, the position of the upper end of the sleeve 94 is determined by a stop shoulder 116 in the top of the box m2. The provision of the ports 115 and the spacing of the end of the rotor shaft 2% from the end of the sleeve 94 permits drilling mud to enter the bore 45 of the drill shaft 15 from the annular space 27 to equalize mud p'essures and render it unnecessary for an excess of mud to travel through the slots or ports 3? in the stator elements 80 of the thrust bearing units 40.

Possible back flow of the combined mud streams entering the box element 1d of the drill shaft 15 from the bore 45 and from the annular space 27 via the slots 33 of the stator elements 853 and the shaft ports 46, as when the drill string is being lowered into a well filled with mud, is prevented by the previously mentioned check valve 43 which is carried in the box element 14 by means of a cage 12% mounted in a corresponding bore. The valve 48 is urged up to its seat by a spring 122 disposed about a valve stem 123 mounted in a guide hub 1Z4 centrally positioned by a spider 1255. To prevent mud leakage or by-passiug at other places where objectionable,

splines 8 rubber .O-ring packings are used, such as shown in partition sleeve and diverter Z5 and in the top and bottom bearing plates 54 and 64 of the fluid motor 22.

The rubber elements in the various bearings 16, 3%, 32 and 43, whether the rubber be natural or synthetic, provide for a limited but important amount of play between the parts, absorb significant amounts of vibration, and avoid much mechanical wear in the respective locations.

Operation With the apparatus assembled and installed as shown, passage of pressurized drilling mud into the drill string from the earths surface results in the movement of a portion of the mud into the flow bean 44a at the top of the fluid motor and down through the bore 44 thereof to the bore 45 in the drill shaft and thence past the check valve 48 to the drill bit 12 to lubricate the latter and circulate the cuttings up to a settling basin at the surface. Another portion of the drill mud enters the fluid motor 22 through the inlet ports 34 in its housing 24 and travels down through the vertical passages '70 to the outlet ports 35 while working against the rotor vanes 72 to drive the rotor and its shaft 20, as previously described.

Such rotation acts through the coupling 18 and its sleeve parts 94 and 1th} to drive the drill shaft 15 and the drill bit 12 attached thereto. The rotor works in its bearings and 32, while the drill shaft 15 works in its rubber bearing 16 at the bottom of the pipe section 10 and within the plurality of thrust bearings 49 which acts to transfer the weight load of the drill string to the drill shaft shoulder 88 and thereby to the drill bit 12 for proper drilling pressure as usual. The drill mud escaping from the outlet ports of the fluid motor passes down through the annular mud passage 27 outside the motor housing 24, and thence in part through the ports 15 in the coupling sleeve 1% to the bore in the drill shaft 15, and in part through the ports or slots 38 in the thrust bearing units 4% to the ports in the lower end of the drill shaft 15, whereby all mud is commingled in the box element 14 thereof to pass the check valve and supply the drill bit 12.

The heavy compression type coil spring lllti which is made effective between the ends of the rotor shaft 20 and the drill shaft 15 is quite important to insure long life of the upper motor bearing from which the rotor and its integral rotor shaft 20 are suspended. In functioning, the compression spring lit) places an up-thrust load against the thrust bearing 32 at the lower end of the motor 22. This relieves the load on the upper hearing 3% to a significant and important extent. In operation, high pressure drilling mud coming down the drill string imposes a high thrust load upon the upper end of the rotor shaft The upper bearing 36 tends to absorb this load, but at the expense of much of its life. The heavy coil spring lid effectively and significantly reduces such load and considerably increases the life of the upper bearing 33. By making the spring relatively heavy it easily provides an entirely adequate offsetting up-tlirust on the lower end of the rotor shaft 2d. By the ready adjustment of the spring seat or collar 112 and its locknut 3.14, as provided here, a suitable offsetting thrust load is easily effected. Thus, this can readily be made to equal for example approximately that load produced by a flow of drilling mud of about 200 gallons per minute at a pressure of about 500 pounds per square inch Since the splined parts of the coupling 13 are free to slide within reasonable limits on each of the rotor shaft 26 and drill shaft 15, load against the spring 1163 is transmitted to the d ill shaft, but some of this down thrust produced by me flowing rnud is counteracted by up-thrust of the mill bit 12 when working on the bottom of the well hole during drilling. The coil spring lit) between the two shafts l3 and 26 provides a resilient,

gage.

partially self-adjusting means for transmitting and equalizing these forces.

I claim:

1. In a deep-well rotary m'otor drill combination:

a length of drill pipe adapted to be attached at its upper end to a drill pipe string;

a drill shaft having at its lower end bit-mounting means and mounted in the lower end portion of said pipe length to rotate;

a fluid motor having an elongated outer housing in the upper portion of said pipe length above said drill shaft operable by drilling mud;

spacing means between said housing and said pipe length fixedly mounting said housing in said pipe length and providing annular fluid passages within said pipe length above and below such spacing means;

a driven rotor shaft concentrically mounted in said fluid-motor housing and providing a rotor body rotating in said housing to drive said drill shaft;

bearing means rotatably mounting the upper end of said rotor shaft at the upper end of said motor housing;

means providing inlet ports in said housing above said spacing means for entrance of drilling mud to drive said rotor body and its shaft, and outlet ports below said spacing means leading into the annular passage below said spacing means for discharge of drilling mud;

a thrust bearing assembly disposed between said drill shaft and said pipe length below said rotor shaft and its bearing means and transferring the load of said pipe length and drill string to said drill shaft and longitudinally yieldable;

coupling means between said driven rotor shaft and said drill shaft above said thrust bearing assembly for effecting rotary drive of said drill shaft from said rotor shaft.

2. A combination as in claim 1 including in said cou pling means an up-thrust-spring between said shafts stabilizing the coupling joint and transmitting down-thrust rotor load to said drill shaft.

3. A combination as in claim 1 wherein said bearing assembly includes a plurality of yieldable bearing units.

4. A combination as in claim 1 including bearing means for the lower end of the rotor shaft and sleeve bearing means below the thrust bearing assembly and Within the lower end of said drill pipe length for the lower end of said drill shaft.

5. A combination as in claim 1 wherein said fluid motor is provided with flexible driving vanes mounted thereon.

6. A combination as in claim 1 wherein a bearing is provided in said motor for the lower end of said rotor body above said coupling means.

References Cited in the file of this patent UNITED STATES PATENTS 1,072,964 Maher et al Sept. 9, 1913 1,790,460 Capeliuschnicolf J an. 27, 1931 1,965,564 Bannister July 10, 1934 2,371,248 McNamara Mar. 13, 1945 2,613,917 Postlewaite Oct. 14, 1952 2,655,344 McDonald Oct. 13, 1953 2,783,971 Carle et al Mar. 5, 1957 2,852,230 Garrison Sept. 16, 1958 3,012,618 Hoagland Dec. 12, 1961 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,076,514 February 5, 1963 Marion A Garrison I It is hereby certified that error appears in the above numbered pat- I ent requiring correction and that they said Letters Patent should read as corrected below.

Column 9, lines 33 and 34, for "shaft and longitudinally yieldable;-" read shaft; and column 10, line 1, before "coupling" insert longitudinally yieldable Signed and sealed this 14th day of July 1964.

(SEAL) Attest:

ESTON G. JOHNSON EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. IN A DEEP-WELL ROTARY MOTOR DRILL COMBINATION: A LENGTH OF DRILL PIPE ADAPTED TO BE ATTACHED AT ITS UPPER END TO A DRILL PIPE STRING; A DRILL SHAFT HAVING AT ITS LOWER END BIT-MOUNTING MEANS AND MOUNTED IN THE LOWER END PORTION OF SAID PIPE LENGTH TO ROTATE; A FLUID MOTOR HAVING AN ELONGATED OUTER HOUSING IN THE UPPER PORTION OF SAID PIPE LENGTH ABOVE SAID DRILL SHAFT OPERABLE BY DRILLING MUD; SPACING MEANS BETWEEN SAID HOUSING AND SAID PIPE LENGTH FIXEDLY MOUNTING SAID HOUSING IN SAID PIPE LENGTH AND PROVIDING ANNULAR FLUID PASSAGES WITHIN SAID PIPE LENGTH ABOVE AND BELOW SUCH SPACING MEANS; A DRIVEN ROTOR SHAFT CONCENTRICALLY MOUNTED IN SAID FLUID-MOTOR HOUSING AND PROVIDING A ROTOR BODY ROTATING IN SAID HOUSING TO DRIVE SAID DRILL SHAFT; BEARING MEANS ROTATABLY MOUNTING THE UPPER END OF SAID ROTOR SHAFT AT THE UPPER END OF SAID MOTOR HOUSING; MEANS PROVIDING INLET PORTS IN SAID HOUSING ABOVE SAID SPACING MEANS FOR ENTRANCE OF DRILLING MUD TO DRIVE SAID ROTOR BODY AND ITS SHAFT, AND OUTLET PORTS BELOW SAID SPACING MEANS LEADING INTO THE ANNULAR PASSAGE BELOW SAID SPACING MEANS FOR DISCHARGE OF DRILLING MUD; A THRUST BEARING ASSEMBLY DISPOSED BETWEEN SAID DRILL SHAFT AND SAID PIPE LENGTH BELOW SAID ROTOR SHAFT AND ITS BEARING MEANS AND TRANSFERRING THE LOAD OF SAID PIPE LENGTH AND DRILL STRING TO SAID DRILL SHAFT AND LONGITUDINALLY YIELDABLE; COUPLING MEANS BETWEEN SAID DRIVEN ROTOR SHAFT AND SAID DRILL SHAFT ABOVE SAID THRUST BEARING ASSEMBLY FOR EFFECTING ROTARY DRIVE OF SAID DRILL SHAFT FROM SAID ROTOR SHAFT. 